Liquid epoxy resins have a long history. Liquid epoxy resins used in combination with liquid curing agents have high handling properties. For this reason, such epoxy resins are useful and advantageous in that they can provide firm molded bodies in a simple manner, and are used as the resin alone or as a composite material. Because of these favorable properties, the epoxy resins are used in broad applications in a variety of fields, such as dental materials, a variety of structure materials, LED sealing materials, adhesives, and coating materials including hard coats (for example, see Patent Documents 1 and 2).